This project will systematically investigate the effect upon drug abuse treatment outcomes of variations in the degree of behavioral structure provided by the treatment program. The studies will be conducted in a community outpatient drug abuse treatment clinic providing opioid maintenance pharmacotherapy -- either methadone or levo-alpha- acetylmethadol (LAAM). Opioid abusers in maintenance pharmacotherapy often have high rates of nonopioid drug use, and many have the diagnosis of antisocial personality disorder (APD), which is associated with poor treatment compliance, poor treatment response, and increased HIV risk. These studies will evaluate a novel behavioral contingency procedure for enhancing compliance with concurrent nonpharmacological treatments and for improving treatment outcomes. An important secondary goal is to assess the relationship to treatment outcome of individual differences in patients' psychiatric/behavioral characteristics. In particular, we will assess the role of antisocial personality disorder and of concurrent illicit cocaine abuse as possible markers or modulators of treatment outcome. Studies 1 and 2 evaluate a behaviorally contingent pharmacotherapy procedure in which continued pharmacotherapy is contingent upon participation in the prescribed behavioral treatments. In both studies volunteer patients will be randomized to contingent versus noncontingent treatment. Study 1 will evaluate this behavioral intervention during methadone pharmacotherapy. Study 2 will evaluate the behavioral intervention during LAAM pharmacotherapy. Outcomes in the two contexts may differ because the two pharmacotherapies require different clinic visit frequencies, and this difference in behavioral structure may influence the efficacy of the behavioral contingency. Study 3 will specifically evaluate whether differences in clinic visit frequency influence treatment outcome. LAAM patients will be randomly assigned to visit the clinic 3 days versus 7 days per week. Outcome measures to be assessed in all three studies include treatment retention, attendance/participation in the behavioral treatment services urinalysis evidence of drug use, plus global clinical outcome indices such as the Addiction Severity Index. These studies will provide important information about the efficacy of the behaviorally contingent pharmacotherapy procedure, about the role of behavior structure in treatment efficacy, and about the relationship of antisocial personality and cocaine use to treatment response. The results will be valuable for guiding the development of integrated behavioral- pharmacological treatments for drug abuse and for guiding the development of effective strategies for patient-treatment matching.